after airbrushing the hull of a tank for example one part wil dry the way i want it to and the other part lighter

am i apply too much paint on the good part or am i applying an uneven layer of paint?

the only way i i got rid of this problem is addplying a coat of paint sealer thi give me the a really nice uniform color but some times this backfires and ruins the whole model ( the clear coat is harmful to thempaint)

all i want to know is that will a clear coat of acrylic solve this problem like the clear coat spray im using now?

Armorjunior (my I call you AJ),
I would think your not applying the paint evenly enough.
What type of paint are you using?
Do you undercoat/prime the model first and make sure there's no grease etc. on it?
If your using enamel, let the paint dry thoroughly (I normally leave it at least 24 hours) before re-coating or whatever. this gives the paints 'carrier' (the clear liquid visible on the surface before you mix it) time to evaporate. If you apply a coat of sealer too soon you stop this happening and can have all sorts of problems. Ideally with enamel paint use an acrylic sealer (although after a long enough gap oil based sealer can be used)
If your using acrylic paint do the reverse and try an oil based sealer.
Try and practice on some scrap platic or something until you find something that works for you.
hope I've helped.
Tom

The most cost effective clear sealer is Johnsons Future - it'll be with floor polishes in your local super market. It is thin enough to spray straight out of the bottle, and you will need to clean airbrush with either blue windex or rubbing alcohol afterwards.

With regardd to the different colours i agree with the above - it sounds like you have an uneven layer of paint - try to remember that lots of very thin layers are better than one thick one - it takes time to get a perfect finish - and a lot of practice.

HTH

Andy

ps

You might want to try typing a bit slower and trying to construct your sentences a bit better - some of your posts are very difficult to read, do you read them back to yourself before hitting the submit button? Sorry to sound like a teacher, but it may help you get more responses.